Facebook and Google in particular are facing fierce pushback following disclosures that Kremlin-linked groups used online ad platforms to try to disrupt the 2016 election, and this week, Democratic Senators Mark Warner (who is helping lead the Senate's Russian Federation investigation) and Amy Klobuchar introduced the Honest Ads Act, which imposes strict rules on the disclosures online platforms make when serving up political ads.

The move by Democratic Senators Mark Warner and Amy Klobuchar, and Republican John McCain on October 19 comes on the heels of allegations that Russian Federation used anonymous ads on social media platforms to meddle and influence opinions during the last year's US presidential election.

Wednesday, Sen. John McCain of Arizona became the first Republican to cosponsor the Honest Ads Act, which was introduced by Democratic Sens. The bill aims to increase transparency about who is funding online political advertisements and, potentially, revealing what kind of motives may lie behind them. Following Facebook's disclosure of the ads, Twitter found some accounts that were linked to them, plus others that weren't linked.

Citizens and politicians alike have called on tech companies to exercise a greater degree of responsibility in keeping these types of ads off their sites, and the newly presented legislation, the Honest Ads Act, aims to force their hand on the matter.

The proposed rules mirror some of the disclosure requirements imposed on broadcasters, who must make copies of political ads run on their airwaves available for public viewing.

It was expected that the bill would be officially introduced today and that's exactly what just happened.

The two Democratic lawmakers decried the lack of transparency in the digital political ad space, arguing the origin and content of the Russian ad buys "are a mystery to the public because of outdated laws that have failed to keep up with evolving technology".

Klobuchar said that "we all know that Russian threats to our national security don't always involve traditional weapons of war".

All three companies have been invited to testify publicly in front of the Senate Intel panel next month, and the House Intelligence Committee is working on its own open hearing on Russia's use of social media.

"Our entire democracy was founded on the simple idea that the people in our country should be self-governing", said Senator Amy Klobuchar of Minnesota, the ranking Democrat on the Rules Committee, which has jurisdiction over federal elections, at a news conference.

Warner and Klobuchar said they were not certain about the bill's prospects in Congress but that they hoped to get something passed by early next year or to have the provisions attached to another piece of legislation.

Facebook plans to send Colin Stretch, the company confirmed on Thursday.

At least two congressional committees and special counsel Robert Mueller are conducting probes into the allegations and to investigate whether there was any collusion with members of the Trump campaign team. From Twitter, it'll be acting General Counsel Sean Edgett, a spokeswoman said.